During flight preparation or during a rerouting, the crew enters its flight plan onto a dedicated computer: the FMS (Flight Management System).
On the basis of the flight plan defined by the pilot, the trajectory is calculated according to the geometry defined by the flight segments and the crossing points (generally referred to as LEGS as defined in Arinc 424 norm, flight segments representing the path of the leg and crossing points their termination) and/or the altitude and speed conditions. A trajectory part allowing two flight segments to be interconnected is referred to as a transition.
In certain cases, one or more transitions may be in conflict. A conflict refers to a discontinuity of the trajectory in the transitions. FIG. 1a shows a first example of conflict between two successive transitions.
FIG. 1a shows a flight plan comprising three consecutive flight segments L1, L2, L3 and a first transition T1 between the first segment L1 and the second segment L2 on the one hand, and, on the other hand, a second transition T2 between the second segment L2 and a third segment L3. A discontinuity exists between the two transitions.
FIG. 1b shows an example of conflict resolution for the example previously presented. In this example, the turn of the second transition (to the right) is in the opposite direction to the turn of the first transition (to the left).
The resolution of the conflict therefore comprises the determination of a straight line tangential to the two turns, which are then connected via this tangent.
FIG. 2a shows a flight plan comprising three consecutive flight segments L1, L2, L3 and a first transition T1 between the first segment L1 and the second segment L2 on the one hand, and, on the other hand, a second transition T2 between the second segment L2 and a third segment L3. A discontinuity exists between the two transitions.
FIG. 2b shows an example of conflict resolution for the example previously presented. In this example, the turn of the second transition (to the left) is in an identical direction to the turn of the first transition (to the right).
The resolution of the conflict comprises the determination of a capture segment of the third segment L3 on the basis of the first transition. The trajectory between the first segment L1 and the third segment L3 comprises the first transition T1 and the determined capture segment.
FIG. 3a shows an example of consecutive conflicts. FIG. 3a shows a flight plan comprising four consecutive flight segments L1, L2, L3, L4 and a first transition T1 between the first segment L1 and the second segment L2, a second transition T2 between the second segment L2 and a third segment L3, a third transition T3 between the third segment L3 and a fourth segment L4. A first conflict exists between the first and the second transition and a second conflict between the second (T2) and the third transition (T3).
FIG. 3b shows an example of multiple conflict resolution. The conflict resolution comprises the determination of a straight line tangential to the first and the second transition. The trajectory between the first segment L1 and the second segment L2 comprises a portion of the first transition, a portion of the tangential straight line, a portion of the second transition and a joining segment (R1) to the second segment L2.
The disadvantage of this solution lies in obtaining a trajectory which deviates from the trajectory defined by the pilot. Furthermore, this solution distances the joining point of the fourth segment L4, which may potentially generate a third transition conflict.
International application WO 2008/054914 discloses a method for resolving transition conflicts on the basis of three consecutive legs.